coagulator

Cauterization

Cauterization is a medical term describing the burning of the body to remove or close a part of it. The main forms of cauterization used today are electrocautery and chemical cautery. Cautery can also mean the branding of a human, either recreational or forced. Accidental burns can be considered cauterization as well.

History

Cauterization was used to stop heavy bleeding, especially during amputations. The procedure was simple: a piece of metal was heated over fire and applied to the wound. This would cause tissues and blood to heat rapidly to extreme temperatures in turn causing coagulation of the blood thus controlling the bleeding, at the cost of extensive tissue damage.

Later, special medical instruments called cauters were used to cauterize arteries. These were first described by Abu al-Qasim al-Zahrawi (Abulcasis) in his Kitab al-Tasrif. Abu al-Qasim al-Zahrawi also introduced the technique of ligature of the arteries as an alternative to cauterization. This method was later improved and used more effectively by Ambroise Paré.

Electrocautery

Electrocauterization (also called electric surgery or electrosurgery) is the process of destroying tissue with electricity and is widely used in modern surgery. The procedure is frequently used to stop bleeding of small vessels (larger vessels being ligated) or for cutting through soft tissue i.e. abdominal fat in a laparotomy or breast tissue in a mastectomy.

Electrocauterization is preferable to chemical cauterization because chemicals can leach into neighbouring flesh and cauterize outside of the intended boundaries.

Electrosurgical generator

The Electrosurgical generator (ESG), more commonly referred to as an electrosurgical unit (ESU) or simply as a generator, powers an electrosurgical system with electricity at an appropriate voltage, frequency and waveform for cutting or for coagulation, as required.

Frequency

To prevent electric shock, an alternating frequency that is higher than power from standard wall outlets is used. Normal AC "house-current" runs at 50–60 Hz and is quite lethal, since at every alteration nerves and muscles get stimulated, causing violent cramps 50–60 times a second. However, nerve and muscle stimulation cease at 100 kHz due to alterations being too fast for the cells to pick up, permitting that Electrosurgery may be performed safely at these “radio” frequencies above 100 kHz.

Cutting vs. coagulation

Different cauterizing effects can be achieved by changing the voltage of the current as well as the pattern of electric pulses. When lower voltage is used with a continuous alternating current (AC), heat is produced very fast and tissue is completely vaporized at the tip of the probe. The effect is dubbed "cutting". When a higher voltage current is used in a pulsed manner, heat is produced more slowly, tissue damage is more widespread (a few mm from the probe) and blood coagulates, and in many electrosurgery instruments this is called "coagulation" mode). This is also used for ablation. Usually a "blend" setting is available as well.

Monopolar vs. bipolar

Two kinds of electrocautery are used, monopolar and bipolar (aka. monothermy and diathermy, respectively). Both involve high frequency alternating current and a pair of electrodes, one called active and the other returning. The difference lies in the placement of these electrodes:

Monopolar: Current is passed from the probe (active electrode) where cauterization occurs and the patient's body serves as a ground. A grounding pad (returning electrode) is placed on the person's body, usually the thigh, and it carries the current back to the machine. Careful application of the return electrode is necessary as extensive burns can occur undetected if the electrode is not correctly positioned.

Bipolar: The active and receiving electrodes are both placed at the site of cauterization. The probe is usually in the shape of a forceps with each tine forming one electrode, cauterizing only the tissue between the electrodes.

Probes

Different shapes of cautery probes are used for different purposes. A common monopolar probe is pen-shaped but ending in a small slender scalpel-shaped spatula of about 5 by 30 mm. This can serve both as a coagulator and as an electric scalpel. The typical bipolar probe resembles a pair of tweezers which grasp and cauterize a small piece of tissue. Variants of these probes are used both in open surgery and in modern minimally invasive surgery. The surgeon operates the probe either by pushing a button on its shaft or with a foot pedal.

Alternate burnsites

When using monopolar electrocautery it is important that the grounding pad be the only way by which the current passes through the body. Electricity always follows the path of least resistance, and if that is via some ground-connected piece of metal touching the patient by chance, a burn might result there as well as at the tip of the cautery probe. Thus great care must be taken that the patient be insulated from the ground and that the large grounding pad be thoroughly attached to the patient. Defects in insulation of the monopolar instrument and capacitative coupling can lead to trauma to non-target tissue.

Chemical cautery

Many chemical reactions can destroy tissue and some are used routinely in medicine, most commonly for the removal of small skin lesions (i.e. warts or necrotized tissue) or hemostasis. The disadvantages are that chemicals can leach into areas where cauterization was not intended. For this reason, laser and electrical methods are preferable, where practical. Some cauterizing agents are:

Silver nitrate: Active ingredient of the lunar caustic, a stick that traditionally looks like a large match-stick. It is dipped into water and pressed onto the lesion to be cauterized for a few moments.

Cantharidin: An extract of the blister beetle that causes epidermal necrosis and blistering; used to treat warts.

Nasal cauterization

If a person has been having frequent nose bleeds, it is most likely caused by an exposed blood vessel in their nose. Even if the nose is not bleeding at the time, it is cauterized to prevent future bleeding. The different methods of cauterization include burning the affected area with acid, hot metal, lasers, or silver nitrate. Such a procedure is naturally quite painful. Sometimes liquid nitrogen is used as a less painful alternative, though it is less effective. In the few countries that permit the use of cocaine for medicinal purposes, it is occasionally used topically to make this procedure less uncomfortable, cocaine being the only local anesthetic which also produces vasoconstriction, making it ideal for controlling nosebleeds.

Religious beliefs

Some followers of Islam believe that cauterization is prohibited, as can be found in Sahih Bukhari.

Volume 7, Book 71, Number 584
Narrated Ibn 'Abbas:

(The Prophet said), "Healing is in three things: A gulp of honey, cupping, and branding with fire (cauterizing)." But I forbid my followers to use (cauterization) branding with fire."

Volume 7, Book 71, Number 587:

Narrated Jabir bin Abdullah:

I heard the Prophet saying, "If there is any healing in your medicines, then it is in cupping, a gulp of honey or branding with fire (cauterization) that suits the ailment, but I don't like to be (cauterized) branded with fire."

In spite of the above, several cases of thermal cauterization are seen in Arabic countries.